Aerial refueling, or “in-flight” refueling, has long been used to increase the endurance of an aircraft. In general terms, a fuel supply carried within a supply aircraft, commonly known as a “tanker,” is transferred to a receiving aircraft that typically follows the tanker and engages a fuel transfer device that is deployed from the tanker. Following the engagement, fuel is transferred from the tanker to the receiving aircraft through the fuel transfer device. Following the transfer of a desired amount of fuel, the receiving aircraft disengages the fuel transfer device and departs.
In one commonly used aerial refueling system, known as the “probe and drogue” system, a retractable hose is deployed from the tanker that includes a drogue or “basket” coupled to a trailing end of the hose. The drogue further includes a valve positioned on an inner portion of the drogue that interrupts a flow of fuel to the receiving aircraft when the aircraft disengages the drogue. The receiving aircraft includes a probe that extends forwardly from the receiving aircraft that is configured to engage the valve positioned within the drogue, so that the receiving aircraft may receive fuel from the tanker.
In another commonly used aerial refueling system, known as the “boom and receiver” system, the fuel transfer device comprises a boom that is coupled to a rear portion of the tanker. The boom includes an elongated, rigid and hollow shaft operable to transfer the fuel, and a telescoping extension portion positioned at an end of the boom. The telescoping extension portion includes a valve configured to be received by a corresponding fuel receiver on the receiving aircraft. The boom also includes a ruddervator assembly generally comprised of airfoils that permit the tanker to controllably maneuver the boom relative to the receiving aircraft. Accordingly, during an aerial refueling operation, the tanker will release the boom from a stowed position and extend the telescoping portion of the boom. The boom may then be directed towards the receiving aircraft by controlling the aerodynamic surfaces to guide the end of the boom into the fuel receptacle on the receiving aircraft. While the boom and the receiver portion are coupled, the telescoping extension portion permits fuel to be continuously transferred by accommodating small relative motions occurring between the tanker and the receiving aircraft.
Although the foregoing aerial refueling systems achieve desirable results, certain drawbacks exist. In particular, an incompatibility exists between tanker aircraft that are configured with the boom and receiver system and a receiving aircraft configured for the probe and drogue system. In order to permit refueling operations between tankers having a refueling boom and probe-equipped receiver aircraft, a refueling adapter, as shown in FIG. 1 may be employed. The refueling adapter 10 includes a hose 12 having a drogue 14 positioned at one end, and a boom-mating portion 16 positioned on an opposing end. The boom-mating portion 16 is configured to be removably coupled to the telescoping extension portion 18 of the boom 20, so that fuel within the tanker (not shown in FIG. 1) may be transferred to the drogue 14. During an aerial refueling operation employing the refueling adapter 10, the boom 20 is released from the stowed position, and controllably maneuvered towards the receiving aircraft (also not shown in FIG. 1). Although FIG. 1 shows the refueling adapter 10 in a non-flight condition, with the hose 12 and the drogue 14 depending downwardly from the boom 20, it is nevertheless understood that while the tanker is in flight, the hose 12 and the drogue 14 extend generally outwardly and behind the boom 20 due to aerodynamic drag. When the boom 20 having the refueling adapter 10 is properly positioned, the probe of the receiving aircraft engages the drogue and receives fuel.
One drawback associated with the foregoing refueling adapter 10 is that it must be installed on the boom 20 prior to flight, and cannot be removed while the tanker is in flight. Consequently, once the boom 20 is configured with the refueling adapter 10, the tanker cannot refuel an aircraft configured for the boom and receptacle equipped receiver system.
What is needed in the art is an improved aerial refueling system that is interoperable, so that a tanker configured for the boom and receptacle system may also be configured to refuel aircraft configured with the probe and drogue system without employing a ground-mounted adaptor.